Recently, bio-sensing devices have been developed which include a semiconductor device based on advanced CMOS processing techniques. Conventional biosensing devices typically rely on inert metals, such as gold or platinum, for their electrodes, in order to provide a high level of compatibility with the often corrosive, or otherwise oxidising, environments in which such biosensors may be used, or which may be required for downstream or subsequent processing of the semiconductor device; however, there has been a recent move towards copper electrodes, in order to maximise the compatibility with standard CMOS processing steps and equipment. However, copper is known to suffer from oxidisation and corrosion under conditions where biosensors are used.
A biosensor device is known from United States Patent Application publication number US2009/184,002, which includes at least one electronic element having a metal electrode which may be made from copper or an alloy comprising copper. US2009/184,002 teaches that, whereas in general in biosensor devices noble metals such as gold silver and platinum are used it is preferable to use copper, since this is compatible with advanced semiconductor processing. The copper readily oxidises to form CuxOy, which may then be cleaned later in the processing, in particular in preparation for the application of a self assembled monolayer, which may then act to protect the electrodes from corrosion and to couple biomolecules on top.
It would be desirable to provide a semiconductor device, and a method of manufacturing semiconductor device, which combines the advantages of copper-based electrode technology within the semiconductor device, and inert metal-electrodes for later processing as a biosensing device.